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Changeset 1400


Ignore:
Timestamp:
Aug 6, 2004, 9:06:36 AM (22 years ago)
Author:
eugene
Message:

minor mods

Location:
trunk/doc/pslib
Files:
3 edited

Legend:

Unmodified
Added
Removed

  • trunk/doc/pslib/psLibADD.tex

    r1215 r1400  
    1 %%% $Id: psLibADD.tex,v 1.22 2004-07-13 21:43:09 eugene Exp $
     1%%% $Id: psLibADD.tex,v 1.23 2004-08-06 19:06:36 eugene Exp $
    22\documentclass[panstarrs]{panstarrs}
    33
    … …  
    641641Positional Astronomy Library}.
    642642
     643\subsubsection{Time}
     644
     645Correct time representation is critical in astronomical software.
     646PSLib uses the \code{psTime} structure to represent all time
     647values.  This structure represents a time which is equivalent to TAI
     648(International Atomic Time) and has the following properties:
     649\begin{itemize}
     650\item it represents both seconds and microseconds
     651\item the seconds are continuous (no leap seconds)
     652\item the zero reference point is \tbd{1970/01/01,00:00:10} UTC.
     653\end{itemize}
     654
     655Julian Day (JD) and Modified Julian Day (MJD) are both continuous time
     656representations, with one julian day interval having a length of 86400
     657TAI seconds.  MJD is equal to JD - 2400000.5 and has a zero point
     658equal to that of TAI, while JD has a zero point 0.5 off of TAI.
     659Conversion between \code{psTime} values and MJD and JD are determined
     660from:
     661
     662\begin{verbatim}
     663mjd = psTime.tv_sec/86400.0 + psTime.tv_usec/86400000000.0 + 40587.0;
     664 jd = psTime.tv_sec/86400.0 + psTime.tv_usec/86400000000.0 + 2440587.5;
     665\end{verbatim}
     666
     667The entry below gives the current relationship between JD, MJD, UTC,
     668and TAI, and comes from the reference at
     669\code{http://tycho.usno.navy.mil/leapsec.html}
     670
     671\begin{verbatim}
     672 1961 JAN  1 =JD 2437300.5  TAI-UTC=   1.4228180 S + (MJD - 37300.) X 0.001296 S
     673 1961 AUG  1 =JD 2437512.5  TAI-UTC=   1.3728180 S + (MJD - 37300.) X 0.001296 S
     674 1962 JAN  1 =JD 2437665.5  TAI-UTC=   1.8458580 S + (MJD - 37665.) X 0.0011232S
     675 1963 NOV  1 =JD 2438334.5  TAI-UTC=   1.9458580 S + (MJD - 37665.) X 0.0011232S
     676 1964 JAN  1 =JD 2438395.5  TAI-UTC=   3.2401300 S + (MJD - 38761.) X 0.001296 S
     677 1964 APR  1 =JD 2438486.5  TAI-UTC=   3.3401300 S + (MJD - 38761.) X 0.001296 S
     678 1964 SEP  1 =JD 2438639.5  TAI-UTC=   3.4401300 S + (MJD - 38761.) X 0.001296 S
     679 1965 JAN  1 =JD 2438761.5  TAI-UTC=   3.5401300 S + (MJD - 38761.) X 0.001296 S
     680 1965 MAR  1 =JD 2438820.5  TAI-UTC=   3.6401300 S + (MJD - 38761.) X 0.001296 S
     681 1965 JUL  1 =JD 2438942.5  TAI-UTC=   3.7401300 S + (MJD - 38761.) X 0.001296 S
     682 1965 SEP  1 =JD 2439004.5  TAI-UTC=   3.8401300 S + (MJD - 38761.) X 0.001296 S
     683 1966 JAN  1 =JD 2439126.5  TAI-UTC=   4.3131700 S + (MJD - 39126.) X 0.002592 S
     684 1968 FEB  1 =JD 2439887.5  TAI-UTC=   4.2131700 S + (MJD - 39126.) X 0.002592 S
     685 1972 JAN  1 =JD 2441317.5  TAI-UTC=  10.0       S + (MJD - 41317.) X 0.0      S
     686 1972 JUL  1 =JD 2441499.5  TAI-UTC=  11.0       S + (MJD - 41317.) X 0.0      S
     687 1973 JAN  1 =JD 2441683.5  TAI-UTC=  12.0       S + (MJD - 41317.) X 0.0      S
     688 1974 JAN  1 =JD 2442048.5  TAI-UTC=  13.0       S + (MJD - 41317.) X 0.0      S
     689 1975 JAN  1 =JD 2442413.5  TAI-UTC=  14.0       S + (MJD - 41317.) X 0.0      S
     690 1976 JAN  1 =JD 2442778.5  TAI-UTC=  15.0       S + (MJD - 41317.) X 0.0      S
     691 1977 JAN  1 =JD 2443144.5  TAI-UTC=  16.0       S + (MJD - 41317.) X 0.0      S
     692 1978 JAN  1 =JD 2443509.5  TAI-UTC=  17.0       S + (MJD - 41317.) X 0.0      S
     693 1979 JAN  1 =JD 2443874.5  TAI-UTC=  18.0       S + (MJD - 41317.) X 0.0      S
     694 1980 JAN  1 =JD 2444239.5  TAI-UTC=  19.0       S + (MJD - 41317.) X 0.0      S
     695 1981 JUL  1 =JD 2444786.5  TAI-UTC=  20.0       S + (MJD - 41317.) X 0.0      S
     696 1982 JUL  1 =JD 2445151.5  TAI-UTC=  21.0       S + (MJD - 41317.) X 0.0      S
     697 1983 JUL  1 =JD 2445516.5  TAI-UTC=  22.0       S + (MJD - 41317.) X 0.0      S
     698 1985 JUL  1 =JD 2446247.5  TAI-UTC=  23.0       S + (MJD - 41317.) X 0.0      S
     699 1988 JAN  1 =JD 2447161.5  TAI-UTC=  24.0       S + (MJD - 41317.) X 0.0      S
     700 1990 JAN  1 =JD 2447892.5  TAI-UTC=  25.0       S + (MJD - 41317.) X 0.0      S
     701 1991 JAN  1 =JD 2448257.5  TAI-UTC=  26.0       S + (MJD - 41317.) X 0.0      S
     702 1992 JUL  1 =JD 2448804.5  TAI-UTC=  27.0       S + (MJD - 41317.) X 0.0      S
     703 1993 JUL  1 =JD 2449169.5  TAI-UTC=  28.0       S + (MJD - 41317.) X 0.0      S
     704 1994 JUL  1 =JD 2449534.5  TAI-UTC=  29.0       S + (MJD - 41317.) X 0.0      S
     705 1996 JAN  1 =JD 2450083.5  TAI-UTC=  30.0       S + (MJD - 41317.) X 0.0      S
     706 1997 JUL  1 =JD 2450630.5  TAI-UTC=  31.0       S + (MJD - 41317.) X 0.0      S
     707 1999 JAN  1 =JD 2451179.5  TAI-UTC=  32.0       S + (MJD - 41317.) X 0.0      S
     708\end{verbatim}
     709
    643710%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    644711

  • trunk/doc/pslib/psLibSDRS.tex

    r1214 r1400  
    1 %%% $Id: psLibSDRS.tex,v 1.61 2004-07-13 21:42:55 eugene Exp $
     1%%% $Id: psLibSDRS.tex,v 1.62 2004-08-06 19:06:36 eugene Exp $
    22\documentclass[panstarrs,spec]{panstarrs}
    33
    … …  
    26612661We require a collection of functions to manipulate time data.  These
    26622662operations primarily consist of conversions between specific time
    2663 formats.  PSLib wraps the libTAI structure \code{taia} for use as the
    2664 native time format. 
     2663formats.  PSLib currently uses the UNIX \code{timeval} structure
     2664representation of time as the native time format.
    26652665\begin{verbatim}
    26662666typedef struct {
    2667   struct taia t;
     2667  time_t         tv_sec;   /* seconds */
     2668  suseconds_t    tv_usec;  /* microseconds */
    26682669} psTime;
    26692670\end{verbatim}
    26702671
    2671 Two utility functions provide the current time in two formats, MJD
    2672 (modified Julian day) and the Sidereal time. 
    2673 
    2674 \begin{verbatim}
    2675 psTime psGetMJD(void);
    2676 psTime psGetSidereal(float mjd, float longitude);
     2672A utility function provides the current time from the system clock, in correct TAI units:
     2673\begin{verbatim}
     2674psTime psTimeGetTime (void);
    26772675\end{verbatim}
    26782676
    … …  
    26982696psTime *psTimevalToTime (struct timeval *input);
    26992697psTime *psTMtoTime (struct tm *input);
     2698\end{verbatim}
     2699
     2700\begin{verbatim}
     2701double psMJDToSidereal (double MJD, double longitude);
     2702double psSiderealToMJD (double sidereal, double longitude);
    27002703\end{verbatim}
    27012704

  • trunk/doc/pslib/psLibSRS.tex

    r1090 r1400  
    1 %%% $Id: psLibSRS.tex,v 1.6 2004-06-25 03:04:46 eugene Exp $
     1%%% $Id: psLibSRS.tex,v 1.7 2004-08-06 19:06:36 eugene Exp $
    22\documentclass[panstarrs]{panstarrs}
    33
    … …  
    8282`gcc' version v2.95 or higher.
    8383
    84 Scripting language must be in \tbd{Python, version TBD}.
     84Scripting language must be in \tbd{Perl, version TBD}.
    8585
    8686\paragraph{Interfaces}
    … …  
    101101convention (line-feed only).  C coding style must adhere to the
    102102standard defined in the document 'Pan-STARRS C-coding standard'
    103 (PSDC-430-004).  \tbd{Python coding must follow the Python standard
     103(PSDC-430-004).  \tbd{Perl coding must follow the Perl standard
    104104defined in the document TBD}.
    105105
    … …  
    179179\paragraph{Commenting and Documentation}
    180180
    181 Commenting of delivered C and Python code must follow the C and
    182 Python coding standards and must provide tags for Doxygen
     181Commenting of delivered C and Perl code must follow the C and
     182Perl coding standards and must provide tags for Doxygen
    183183interpretation of the comments and program structures.
    184184
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